Multi-stage transmission

ABSTRACT

The multi-stage transmission comprises a drive input shaft and a drive output shaft, three single-web planetary gearset assemblies (P 1 , P 2 , P 3 ), at least six rotating shafts ( 1, 2, 3, 4, 5, 6 ) and at least five shift elements ( 03, 04, 13, 16, 45 ) so that six forward gears and one reverse gear can be engaged, such that the drive input shaft ( 1 ) is connected to the solar gearwheel of the first planetary gearset (P 1 ), the annular gearwheel of the first planetary gearset (P 1 ) is in rotationally fixed connection with the housing, the drive output shaft ( 2 ) is connected to the annular gearwheel of the second planetary gearset (P 2 ) and to the web of the third planetary gearset (P 3 ), and the shaft ( 3 ) is permanently connected to the web of the second planetary gearset (P 2 ) and to the annular gearwheel of the third planetary gearset (P 3 ). The shaft ( 4 ) is permanently connected to the solar gearwheel of the second planetary gearset (P 2 ), the shaft ( 5 ) is permanently connected to the web of the first planetary gearset (P 1 ), and the shaft ( 6 ) is permanently connected to the solar gearwheel of the third planetary gearset (P 3 ). The planetary gearset assemblies (P 1 , P 2 , P 3 ) are coupled by means of shafts ( 0, 1, 2, 3, 4, 5, 6 ) and shift elements ( 03, 04, 13, 16, 45 ).

[0001] The present invention concerns a multi-stage transmission ofplanetary structure, in particular an automatic transmission for a motorvehicle, according to the preamble of claim 1.

[0002] Automatic transmissions of the prior art, in particular for motorvehicles, comprise planetary gearset assemblies which are engaged bymeans of frictional or shift elements such as clutches and brakes andare usually connected to a starting element such as a hydrodynamictorque converter or a fluid clutch that can operate with some slippingaction and is optionally provided with a bridging clutch.

[0003] Such a transmission is described in EP 0 434 525 A1. It comprisesessentially a drive input shaft and a drive output shaft arrangedparallel to one another, a dual planetary gearset assembly concentric tothe drive output shaft, and five shift elements in the form of threeclutches and two brakes, whose selective engagement, two at a time,determines the various gear transmission ratios between the drive inputand drive output shafts.

[0004] Furthermore, from DE 199 495 07 A1 by the present applicant amulti-stage transmission is known, in which two non-shifting maingearset combinations are provided, which produce two rotation speeds onthe output side which, besides the speed of the drive input shaft, canoptionally be engaged with a shiftable dual planetary gearset assemblythat acts on the drive output shaft, by selectively closing the shiftelements used in such manner that to shift from one gear to therespective next gear up or down, only one shift element of the two shiftelements actuated at the time has to be engaged or disengaged.

[0005] In addition, within the scope of EP 0 434 525 A1 a multi-stagetransmission is disclosed, which contains a drive input shaft and adrive output shaft arranged in a housing, a planetary gearset assemblyarranged concentrically with the drive output shaft consisting of fourelements denoted as from the first to the fourth in the order of theirspeed, i.e. a so-termed double planetary gearset assembly, and fiveshift elements, namely three clutches and two brakes, whose selectiveactuation in pairs determines various transmission ratios between thedrive input and drive output shafts, such that the transmission has twopower paths which enable six forward gears to be engaged by theselective actuation of the five shift elements two at a time.

[0006] The purpose of the present invention is to propose a multi-stagetransmission of the type described at the start, in which the structuralelaboration is optimised and, in addition, the efficiency in the maingears is improved in relation to slippage and gearing losses.

[0007] According to the invention this objective is achieved by thecharacterizing features of the independent claims 1, 2 and 3. Advantagesand further advantageous design features emerge from the subordinateclaims.

[0008] According to the invention, the multi-stage transmission ofplanetary structure comprises a drive input shaft and a drive outputshaft arranged in a housing, at least three single-web planetary gearsetassemblies, at least six rotating shafts and at least five shiftelements, preferably two brakes and three clutches or three brakes andtwo clutches, whose selective engagement in pairs produces varioustransmission ratios between the drive input and the drive output shafts,so that preferably six forward gears and one reverse gear can beengaged.

[0009] In this case the drive input shaft is connected directly or via aclutch to the solar gearwheel of the first planetary gearset. Inaddition, the drive output shaft is connected to the annular gearwheelof the second planetary gearset and to the web of the third planetarygearset, and another shaft is permanently connected to the web of thesecond planetary gearset and to the annular gearwheel of the thirdplanetary gearset.

[0010] In a first embodiment the annular gearwheel of the firstplanetary gearset is in rotationally fixed connection with the housing.Further, it is provided that another shaft is permanently connected tothe solar gearwheel of the second planetary gearset, a further shaft ispermanently connected to the web of the first planetary gearset, andanother shaft is permanently connected to the solar gearwheel of thethird planetary gearset.

[0011] In a second advantageous embodiment a shaft is permanentlyconnected to the solar gearwheel of the second planetary gearset and tothe web of the first planetary gearset, and another shaft is permanentlyconnected to the solar gearwheel of the first planetary gearset. Inaddition, it is provided that a further shaft is permanently connectedto the solar gearwheel of the third planetary gearset (P3). Both thefirst and the second embodiment comprise two brakes and three clutchesas shift elements.

[0012] Furthermore a third embodiment is proposed, which comprises threebrakes and two clutches. In this case the annular gearwheel of the firstplanetary gearset can be connected to and released from the housing by abrake; a shaft is permanently connected to the solar gearwheel of thesecond planetary gearset, another shaft is permanently connected to theannular gearwheel of the first planetary gearset, and a sixth shaft ispermanently connected to the solar gearwheel of the third planetarygearset.

[0013] In all the embodiments the planetary gearset assemblies,preferably made as negative planetary gearset assemblies, are coupled byshift elements and/or shafts.

[0014] Thanks to the construction according to the invention, suitabletransmission ratios and a considerable increase of the overall spread ofthe multi-stage transmission are obtained, which results in increaseddriving comfort and a significant reduction of fuel consumption.

[0015] The multi-stage transmission according to the invention issuitable for any motor vehicle, in particular for passenger cars andgoods vehicles such as trucks, buses, construction industry vehicles,rail vehicles, caterpillar track vehicles and suchlike.

[0016] Moreover, with the multi-stage transmission according to theinvention, the structural elaboration is reduced considerably by havinga small number of shift elements, namely preferably only three clutchesand two brakes or two clutches and three brakes.

[0017] Advantageously, the multi-stage transmission according to theinvention makes it possible to start up with a hydrodynamic converter,an external starting clutch or even some other suitable externalstarting element. It is also conceivable to enable a starting processwith a starting element integrated in the transmission. Furthermore, themulti-stage transmission according to the invention operates with highefficiency in relation to slippage and gearing losses.

[0018] In addition, the torques in the shift elements and even in theplanetary gearset assemblies are small. This reduces wear in themulti-stage transmission in a particularly advantageous way. Owing tothe low torques in the shift elements and planetary gearset assembliesthe transmission can be made smaller, which optimises the use ofstructural space and leads to cost reduction.

[0019] Furthermore, the transmission according to the invention isdesigned to allow adaptability to various drive train designs, both inthe force-flow direction and from the standpoint of space.

[0020] Below, the invention is explained in greater detail withreference to the drawings, which show:

[0021]FIG. 1 is a schematic view of an example embodiment of amulti-stage transmission according to the invention;

[0022]FIG. 2 is a schematic view of a second example embodiment of amulti-stage transmission according to the invention;

[0023]FIG. 3 is a schematic view of a third example embodiment of amulti-stage transmission according to the invention; and

[0024]FIG. 4 is a shift scheme for the multi-stage transmissionaccording to the invention, as illustrated in FIGS. 1, 2, and 3.

[0025] According to FIG. 1, the multi-stage transmission of planetarystructure according to the invention comprises a drive input shaft 1(An) and a drive output shaft 2 (Ab), which are arranged in a housing,and three single-web planetary gearset assemblies P1, P2 and P3. Theplanetary gearsets P1, P2 and P3 are preferably made as negativeplanetary gearset assemblies. In addition, six rotating shafts 1, 2, 3,4, 5 and 6 and five shift elements, namely two brakes 03, 04 and threeclutches 13, 16, 45 are provided, whose selective actuation two at atime brings about various transmission ratios between the drive inputshaft and the drive output shaft, so that six forward gears and onereverse gear can be engaged.

[0026] As can be seen from FIG. 1, the drive input shaft 1 is connecteddirectly to the solar gearwheel of the first planetary gearset P1 andthe annular gearwheel of the first planetary gearset P1 is permanentlyin rotationally fixed connection with the housing (shaft 0). The driveoutput shaft 2 is connected to the annular gearwheel of the secondplanetary gearset P2 and to the web of the third planetary gearset P3,and the shaft 3 is permanently connected to the web of the secondplanetary gearset P2 and to the annular gearwheel of the third planetarygearset P3. Further, the shaft 4 is permanently connected to the solargearwheel of the second planetary gearset P2, the shaft 5 is permanentlyconnected to the web of the first planetary gearset P1, and the shaft 6is permanently connected to the solar gearwheel of the third planetarygearset P3.

[0027] According to the invention, the shafts 3 and 4 can be coupled tothe housing by the brakes 03 and 04 respectively; the clutch 13 connectsthe shafts 1 and 3 to or releases them from one another, and the clutch16 connects the shafts 1 and 6 to or releases them from one another,while the clutch 45 connects the shafts 4 and 5 to or releases them fromone another.

[0028] The embodiment shown in FIG. 2 differs from the embodimentaccording to FIG. 1 in that the drive input shaft is not connecteddirectly to any planetary gearset, and the shaft 4 is additionallyconnected to the web of the first planetary gearset P1. Further, theshaft 5 is permanently connected to the solar gearwheel of the firstplanetary gearset P1. Instead of the clutch 45, a brake 05 is providedwhich connects the shaft 5 to or releases it from the housing.

[0029] The fixed connection of the web of the first planetary gearset P1to the housing, as in the two embodiments already explained, can bereplaced by a releasable connection, for example a brake.

[0030] This enables an electric motor or other suitable additional drivesource to be arranged on the shaft 0 released by means of the brake.

[0031]FIG. 3 shows another example embodiment of a multi-stagetransmission of planetary structure according to the present invention,which differs from the example embodiment of FIG. 1 in that the shaft 4is additionally connected to the web of the first planetary gearset P1and the shaft 5 is permanently connected to the annular gearwheel of thefirst planetary gearset P1. As can be seen from the figure, instead ofthe clutch 45 a clutch 15 is provided, which connects the shafts 1 and 5to or releases them from one another.

[0032] The corresponding shift scheme of the example embodimentsdiscussed above is the object of FIG. 4, in which, as examples,transmission ratios i and the resulting speed transitions f are alsoindicated.

[0033] As shown, the multi-stage transmission according to the inventionhas a progressive gear variation. Furthermore, when shiftingsequentially double-shifts are avoided, since two adjacent gears in eachcase use only one common shift element. Furthermore, any desired shiftbetween the first and fourth gear and between the fourth and the sixthgear involves the actuation of only one shift element. In the firstembodiment shown in FIG. 1, for gears 1 to 4 the clutch 16 ispermanently actuated; these gears are engaged by the additionalactuation of the brake 03 (first gear), the brake 04 (second gear), theclutch 45 (third gear) and the clutch 13 (fourth gear). For gears 4 to6, the clutch 13 remains closed and the gears are engaged by theadditional actuation of the clutch 45 (fifth gear) and the brake 04(sixth gear). According to the invention, engaging the reverse gearrequires the actuation of the brake 03 and the clutch 45.

[0034] The shift scheme for the embodiments of FIGS. 2 and 3 isanalogous, with the difference that instead of the clutch 45, the brake05 or the clutch 15 is actuated.

[0035] According to the invention, at any suitable point in themulti-stage transmission additional freewheels can be provided, forexample between a shaft and the housing or in order to divide or toconnect a shaft.

[0036] In addition, thanks to the structure according to the inventionthe drive input and output shafts can be arranged either on the sameside of the transmission or on opposite sides. In addition, an axledifferential or a transfer differential can also be arranged on thedrive input or drive output of the transmission.

[0037] In an advantageous further development, the drive input shaft canif necessary be separated from a drive motor by a coupling element, andas that coupling element a hydrodynamic converter, a hydraulic clutch, adry starter clutch, a fluid starter clutch, a magnetic powder clutch ora centrifugal clutch can be used.

[0038] Such a starting element can also be arranged after thetransmission, and in that case the drive input shaft is in fixedconnection with the crankshaft of the engine. According to theinvention, starting can also take place by means of a shift element ofthe transmission, preferably by means of the brake 04, the brake 03 orthe clutch 16.

[0039] The multi-stage transmission according to the invention alsoenables a torsional oscillation damper to be arranged between the engineand the transmission.

[0040] In a further embodiment of the invention (not illustrated), awear-free brake can be arranged on any shaft, preferably in the driveinput shaft or the drive output shaft, and this is of particularimportance especially for use in goods vehicles. An auxiliary driveoutput can also be provided on any shaft for driving additionalaggregates.

[0041] The shift elements used can be made as change-under-load clutchesor brakes; however, disk brakes, band brakes and/or conical clutches canalso be used. Furthermore, form-enclosing brakes and/or clutches such assynchromesh or claw clutches can be used.

[0042] A further advantage of the multi-stage transmission proposed hereis that an electric machine can be connected to any shaft as a generatorand/or as an additional drive.

[0043] Clearly, any design structure and in particular any spatialarrangement of the planetary gearset assemblies and shift elements intheir own right and relative to one another, provided it is technicallyappropriate and does not affect the function of the transmission asindicated in the claims, falls under the protection scope of the presentclaims even if the said structures are not explicitly indicated in thefigures or the description.

[0044] Reference Numerals

[0045]0 Shaft

[0046]1 Shaft

[0047]2 Shaft

[0048]3 Shaft

[0049]4 Shaft

[0050]5 Shaft

[0051]6 Shaft

[0052]03 Brake

[0053]4 Brake

[0054]5 Brake

[0055]6 Clutch

[0056]15 Clutch

[0057]16 Clutch

[0058]45 Clutch

[0059] P1 planetary gearset

[0060] P2 planetary gearset

[0061] P3 planetary gearset

[0062] An Drive input

[0063] Ab Drive output

[0064] i Transmission ratio

[0065] f Speed change

1. Multi-stage transmission of planetary structure, in particular for amotor vehicle, which comprises a drive input shaft and a drive outputshaft arranged in a housing, three single-web planetary gearsetassemblies (P2, P2, P3), at least six rotating shafts (0, 1, 2, 3, 4, 5,6) and at least five shift elements (03, 04, 13, 16, 45) which consistof brakes and/or clutches, whose selective engagement two at a timeproduces various transmission ratios between the drive input and thedrive output shafts so that six forward gears and one reverse gear canbe engaged, characterized in that the drive input shaft (1) is connecteddirectly to the solar gearwheel of the first planetary gearset (P1), theannular gearwheel of the first planetary gearset (P1) is in rotationallyfixed connection with the housing, the drive output takes place via ashaft (2) which is connected to the annular gearwheel of the secondplanetary gearset (P2) and to the web of the third planetary gearset(P3), a shaft (3) is permanently connected to the web of the secondplanetary gearset (P2) and to the annular gearwheel of the thirdplanetary gearset (P3), a shaft (4) is permanently connected to thesolar gearwheel of the second planetary gearset (P2), a shaft (5) ispermanently connected to the web of the first planetary gearset (P1),and a shaft (6) is permanently connected to the solar gearwheel of thethird planetary gearset (P3), such that the shaft (3) can be coupled tothe housing by a brake (03), the shaft (4) can be coupled to the housingby a brake (04), a clutch (13) connects the shafts (1) and (3) to orreleases them from one another, a clutch (16) connects the shafts (1)and (6) to or releases them from one another, and a clutch (45) connectsthe shafts (4) and (5) to or releases them from one another. 2.Multi-stage transmission of planetary structure, in particular for amotor vehicle, which comprises a drive input shaft and a drive outputshaft arranged in a housing, three single-web planetary gearsetassemblies (P2, P2, P3), at least six rotating shafts (0, 1, 2, 3, 4, 5,6) and at least five shift elements (03, 04, 13, 15, 16) which consistof brakes and/or clutches, whose selective engagement two at a timeproduces various transmission ratios between the drive input and thedrive output shafts so that six forward gears and one reverse gear canbe engaged, characterized in that the drive input shaft (1) is connectedvia the clutch (15) to the solar gearwheel of the first planetarygearset (P1), the annular gearwheel of the first planetary gearset (P1)is in rotationally fixed connection with the housing, the drive outputtakes place via a shaft (2) which is connected to the annular gearwheelof the second planetary gearset (P2) and to the web of the thirdplanetary gearset (P3), a shaft (3) is permanently connected to the webof the second planetary gearset (P2) and to the annular gearwheel of thethird planetary gearset (P3), a shaft (4) is permanently connected tothe solar gearwheel of the second planetary gearset (P2) and to the webof the first planetary gearset (P1), a shaft (5) is permanentlyconnected to the solar gearwheel of the first planetary gearset (P1),and a shaft (6) is permanently connected to the solar gearwheel of thethird planetary gearset (P3), such that the shaft (3) can be coupled tothe housing by a brake (03), the shaft (4) can be coupled to the housingby a brake (04), a clutch (13) connects the shafts (1) and (3) to orreleases them from one another, a clutch (16) connects the shafts (1)and (6) to or releases them from one another, and a clutch (15) connectsthe shafts (1) and (5) to or releases them from one another. 3.Multi-stage transmission of planetary structure, in particular for amotor vehicle, which comprises a drive input shaft and a drive outputshaft arranged in a housing, three single-web planetary gearsetassemblies (P2, P2, P3), at least six rotating shafts (0, 1, 2, 3, 4, 5,6) and at least five shift elements (03, 04, 05, 13, 16) which consistof brakes and/or clutches, whose selective engagement two at a timeproduces various transmission ratios between the drive input and thedrive output shafts so that six forward gears and one reverse gear canbe engaged, characterized in that the drive input shaft (1) is directlyconnected to the solar gearwheel of the first planetary gearset (P1),the annular gearwheel of the first planetary gearset (P1) can be put inrotationally fixed connection with, or released from the housing by abrake (05), the drive output takes place via a shaft (2) which isconnected to the annular gearwheel of the second planetary gearset (P2)and to the web of the third planetary gearset (P3), a shaft (3) ispermanently connected to the web of the second planetary gearset (P2)and to the annular gearwheel of the third planetary gearset (P3), ashaft (4) is permanently connected to the solar gearwheel of the secondplanetary gearset (P2) and to the web of the first planetary gearset(P1), a shaft (5) is permanently connected to the annular gearwheel ofthe first planetary gearset (P1), and a shaft (6) is permanentlyconnected to the solar gearwheel of the third planetary gearset (P3),such that the shaft (3) can be coupled to the housing by a brake (03),the shaft (4) can be coupled to the housing by a brake (04), a clutch(13) connects the shafts (1) and (3) to or releases them from oneanother, a clutch (16) connects the shafts (1) and (6) to or releasesthem from one another, and the brake (05) connects the shaft (5) to orreleases it from the housing.
 4. Multi-stage transmission according toclaims 1, 2 or 3, characterized in that the planetary gearsets (P1, P2,P3) are made as negative planetary gearset assemblies.
 5. Multi-stagetransmission according to claims 1, 2 or 4, characterized in that thefixed connection of the annular gearwheel of the first planetary gearset(P1) to the housing can be replaced by a releasable connection by meansof a brake.
 6. Multi-stage transmission according to claim 5,characterized in that an electric machine or another suitable additionaldrive machine can be arranged on the shaft (0) associated with thehousing.
 7. Multi-stage transmission according to any of the precedingclaims, characterized in that freewheels can be inserted at any suitablepoint of the transmission.
 8. Multi-stage transmission according toclaim 7, characterized in that the freewheels can be inserted betweenthe shafts (0, 1, 2, 3, 4, 5, 6) and the housing.
 9. Multi-stagetransmission according to any of the preceding claims, characterized inthat the drive input and the drive output are provided on the same sideof the housing.
 10. Multi-stage transmission according to any of thepreceding claims, characterized in that the drive input and drive outputare provided on opposite sides of the housing.
 11. Multi-stagetransmission according to any of the preceding claims, characterized inthat an axle differential and/or a transfer differential is arranged onthe drive input side or on the drive output side of the housing. 12.Multi-stage transmission according to any of the preceding claims,characterized in that the drive input shaft (1) can be disengaged from adrive engine by a coupling element.
 13. Multi-stage transmissionaccording to claim 12, characterized in that as the coupling element, ahydrodynamic converter, a hydraulic clutch, a dry starter clutch, aliquid starter clutch, a magnetic powder clutch or a centrifugal forceclutch is provided.
 14. Multi-stage transmission according to any of thepreceding claims, characterized in that in the force-flow direction anexternal starting element is arranged after the housing, in particularaccording to claim 13, such that the drive input shaft (1) is in fixedconnection with the crankshaft of the drive engine.
 15. Multi-stagetransmission according to any of the preceding claims, characterized inthat starting takes place by means of a shift element of thetransmission, and the crankshaft of the engine is permanently connectedto the drive input shaft (1).
 16. Multi-stage transmission according toclaim 15, characterized in that the brake (04), the brake (03) or theclutch (16) can be used as the shift element.
 17. Multi-stagetransmission according to any of the preceding claims, characterized inthat a torsional oscillation damper can be arranged between the engineand the transmission.
 18. Multi-stage transmission according to any ofthe preceding claims, characterized in that a wear-free brake can bearranged on any shaft.
 19. Multi-stage transmission according to claim18, characterized in that a wear-free brake can be arranged on the driveinput shaft (1) or the drive output shaft (2).
 20. Multi-stagetransmission according to any of the preceding claims, characterized inthat an auxiliary drive output can be arranged on any shaft to driveadditional aggregates.
 21. Multi-stage transmission according to claim20, characterized in that the auxiliary drive output can be arranged onthe drive input shaft (1) or on the drive output shaft (2). 22.Multi-stage transmission according to any of the preceding claims,characterized in that the shift elements are formed as change-under-loadclutches or brakes.
 23. Multi-stage transmission according to claim 22,characterized in that disk clutches, band brakes and/or conical clutchescan be used.
 24. Multi-stage transmission according to any of thepreceding claims, characterized in that form-enclosing brakes and/orclutches are provided as shift elements.
 25. Multi-stage transmissionaccording to any of the preceding claims, characterized in that anelectric machine can be connected to any shaft as a generator and/or asan additional drive machine.